People with a cynical and suspicious attitude towards others develop dementia more often than other people.

New research shows that people with a negative attitude and poor trust of others develop dementia more often than other people. (Photo: Shutterstock)

Do you trust nobody and do you always believe that other people have a hidden agenda when they do something good? Then it might be time to change our attitude as new research indicates that people with a cynical and somewhat paranoid personality are at higher risk of developing dementia.

On the whole, a hostile and suspicious attitude is quite unhealthy.

“This is a personality trait that in previous studies has been shown to be connected to a number of diseases such as cardio-vascular diseases, cancer and increased mortality,” says Anna-Maija Tolppanen, a postdoc at the University of Eastern Finland. “We were interested in finding whether cynical mistrust also increases the risk of dementia.”

Isolation increases the risk of dementia

Anna-Maija Tolppanen and colleagues from the Karolinska Institute in Sweden have just published their findings in the scientific journal Neurology. In their study, cynical and suspicious people were found to suffer dementia three times more often than the others who took part in the study.

“It could be because people with a high degree of cynical mistrust of other people are less likely to take part in social events than people with more optimistic types of personality,” says Tolppanen. “We know that social isolation increases the risk of dementia.”

Prevention should take personality into account

The Finnish and Swedish researchers reached their result by getting more than 1,000 adults from different age groups to answer questionnaires over several years. The participants had to state whether they agreed or disagreed with statements such as:

“I believe most people are prepared to lie to be successful.”
“It's best not to trust anyone.”
“I always think about the hidden agendas people may have when they are being good to me.”
“Nobody cares very much about what happens to me.”
“Most people have friends in order to exploit them.”

Afterwards, the participants were divided into groups of low, moderate or high cynical distrust. Eight years later, when the participants had an average age of 71 years, 622 of them were tested for dementia. Three times as many of those who were in the high cynical distrust group could be diagnosed as having dementia compared those with a more positive attitude to their fellow human beings.

“The results confirm that taking personality traits into account when preparing preventive strategies can be a good idea,” says Tolppanen. “But as our study is the first that shows a correlation between cynicism and dementia we need more research before we can conclude with certainty that the connection exists.”

Isolation and depression increase the risk of dementia

According to Tolppanen there can be biological as well as psychological causes as to why cynical and suspicious people appear to be more likely to develop dementia. One explanation could be that cynicism and anger bring forth inflammation in the body -- which can lead to cardio-vascular diseases and dementia (see the Factbox).

Another explanation is that cynical and suspicious people live a life that damages the brain's cognitive functions and thereby increases the risk of developing dementia.

“Certain personality traits can result in a person becoming more or less likely to get involved in activities such as social gatherings and exercise,” she says. “These activities have been shown to be beneficial for the brain's cognitive functions. It could also be that personality traits such as cynicism and hostility are related to morphological changes or structural differences in the brain.”

Depression increases the risk of dementia

The Danish Dementia Research Centre finds the Finnish-Swedish research results convincing. According to the centre's neuropsychologist, Kasper Jørgensen, it could very well be that the cynical participants in the study lived their lives in a way that increases the risk of developing dementia.

Facts

In their scientific paper, Anna-Maija Tolppanen and her colleagues argue that cynicism could be related to dementia due to an inflammation marker that's also associated with cardio-vascular diseases. They argue as such:

We know with certainty that cardio-vascular diseases increase the risk of dementia.
We also know that cynical and aggressive people are more susceptible to developing cardio-vascular diseases than other people.

A study published in 2011 showed that both cynicism and cardio-vascular diseases are associated with inflammation in the body. In the study, American researchers found a certain inflammation marker in middle-aged Latin American immigrant women who all had aggressive and cynical traits of character. The same inflammation marker is found in people with cardio-vascular diseases.

It's not unlikely that this inflammation marker is associated with dementia as well, suggest the Finnish and Swedish researchers.

“We know that social isolation is a risk factor and the people with a small network are more likely to develop dementia,” says Jørgensen. “One can imagine that cynical and suspicious people are less social than others and seen in that light it is not surprising if they develop dementia more often.”

He adds that there’s also the possibility that people get depressed more often if they constantly mistrust others.

“We know with great certainty that depression increases the risk of developing dementia,” says Jørgensen.

Comprehensive Danish register studies have shown an almost doubled risk of developing dementia amongst people who suffered from severe and longer-lasting periods of depression throughout their lives.

“This can be because depression wears out the brain, especially the hippocampus, which is one of the brain centres that are also affected when you suffer from the Alzheimer's disease,” says Jørgensen.

Cynical people should get special guidelines

Knowledge about the extent to which different personality traits increase the risk of dementia can perhaps be used in preventive strategies, says Jørgensen.

“If we know that people with certain personality traits are a particularly exposed group then in principle we could target our efforts and give them advice on how they can reduce their risk,” he says.

However, he doesn’t believe that it’s possible to affect people's personalities directly -- but offers a possible solution.

“If some personality traits tend to lead to a lifestyle that increases the risk of dementia then perhaps you can be particularly attentive to this when you give them guidelines for how they can live in a more appropriate way,” says Jørgensen.

Personality is related to health

Another Danish researcher -- Erik Mortensen, who is professor of psychology at the University of Copenhagen – is not surprised that the Finnish-Swedish researchers have found a connection between cynicism and dementia.

During recent decades it has been shown that several personality traits such as aggressiveness, hostility, cynicism and anxiety can be connected with a number of different diseases, he says.

“Since people began doing psychological personality tests, researchers have been able to show that some personality traits are related to poor health to a greater extent than other traits,” says Mortensen.

Although you cannot change your personality, you can learn to live more appropriately with the personality traits that you have, he says.